Let me add some context here:
In Frank Herbert’s Dune, there is this sentence:
“I know the Dark Things and the ways of the Great Mother,” Jessica said. She read the more obvious signs in Mapes’ actions and appearance, the petit betrayals.
If the betrayals are petit, they are not immediately noticeable to normal folks, and only noticeable to Jessica because of her special training regarding such stuff (don’t worry, this is not even a spoiler). What am I missing?